Well, reef ready is a way of indicating whether a tank is drilled or not. You can have a non-reef ready tank and put a HOB overflow on it without drilling. Essentially, you want to have a sump. The sump offers many benefits, especially in saltwater. Some of them are...

-Increases total system volume, thus keeping the tank more stable
-Hides equipment in sump rather than in the display tank
-Gives the ability to run add macro/LR to sump for additional filtration
-Much more flexible for custom filtration and equipment

As far as RR being quieter, that's not always the case. Don't assume all overflows are silent, because a majority are not. Lots of methods have been developed in efforts to silent overflows, notably durso standpipes, stockman standpipes, herbie method, maggie mufflers, and the bean method (modified herbie). Having said that, I have confidence in the bean method and have chosen it and a coast to coast overflow for my next setup, although I have never used it, there have been lots of satisfied 'customers'.